38E Heater

[DrDave]

I have a new to me 2008 Mariner 37 Seville Pilothouse / 38E, hull #8. It has a Hurricane II heater with three zone thermostats in the stateroom, Pilothouse, and guest head. There is an ITR controller beside the Pilothouse thermostat and a heater switch on the AC panel.
There is a summer valve that I have configured to bring the heater in line.
When all systems are turned on the heater heats and cycles normally. There is heat delivered to all of the heating coils, but even with the thermostats set well above ambient temperature none of the fans come on.

Scott tells me that there should be fan speed switches adjacent to each heating unit to control the individual fans, but I cannot find them. Nor can I find a master switch anywhere.

Does anyone have experience with a similar setup, any suggestions as to what the issue is, or where I might find the fan speed switches?

 

[HeadedToTexas]

We have hull #3, but only reverse cycle heaters (for now). Troubleshooting wiring issues is always a challenge, but inevitable. Patience is a virtue. So is a strong back!

 

[Bmarler]

Almost all heater systems are custom install, so have differences to other systems.
Sounds like there’s a power supply to the fans that isn’t turned on, or there’s an aqua stat not functioning properly. The fan control should be relays switched by the thermostats for each zone. Check for power going into the relays, and also that the relays are energized by the thermostats.

 

[HeadedToTexas]

Almost all heater systems are custom install

As are most items I am finding, at least aboard these early Mariner boats. My fuel gauges stopped receiving signals from the tank level senders just before haul out. I'm sure it was me, but I have yet to find what was disconnected. Bet your heater fan thing is similar.

 

[KMAL]

I have a new to me 2008 Mariner 37 Seville Pilothouse / 38E, hull #8. It has a Hurricane II heater with three zone thermostats in the stateroom, Pilothouse, and guest head. There is an ITR controller beside the Pilothouse thermostat and a heater switch on the AC panel.
There is a summer valve that I have configured to bring the heater in line.
When all systems are turned on the heater heats and cycles normally. There is heat delivered to all of the heating coils, but even with the thermostats set well above ambient temperature none of the fans come on.

Scott tells me that there should be fan speed switches adjacent to each heating unit to control the individual fans, but I cannot find them. Nor can I find a master switch anywhere.

Does anyone have experience with a similar setup, any suggestions as to what the issue is, or where I might find the fan speed switches?

I have worked with this system on my previous boat. Each of the fans have aquastats - if the fan units do not get enough heat, the aquastats will keep the fans from coming on. It could be that summer mode is limiting your circulation as well - have you tried winter mode - if I recall that allows for full circulation throughout the system. BTW - the folks at ITR were always very responsive/helpful. Also - you can remove the aquastats and the fans will come on when ever your thermostat demands heat.

These work by circulating heated "coolant" through the system. When a thermostat calls for heat - the aquastats will allow the fans to come on if the coolant at each fan is hot enough. In summer mode, you may not be circulating enough coolant through your system.

 

[Wildbill]

We have a hurricane II heater on a Hatteras LRC, we had a similar episode shortly after the unit was replaced, it was still under warranty, I talked with ITR and they were good at troubleshooting, they indicated that it was an aquastat in the heater itself that would prevent the fans from operating, we were able to obtain this and replace it, it did not improve the situation. After further evaluation by the installer, it was determined that the circuit board was defective, they sent a new circuit board which was replaced, and that gave us back our normal fan operation.

 

[salish]

Possibly low batteries in the thermostats?

 

[mijmoto]

Hey DRDave,

My KK48 has a Chinook system that was a replacement boiler to an existing system. We have experienced aquastat caused "no heat" situations. First, you must find at least one aquastat in your system. They should be located very near the radiators in each heating location. They look like a large hex bolt head with two terminals. You should be able to join the terminals with a jumper which will bypass the aquastat. At this point the fan should come on.

The control board is another source of no heat conditions. Are you sure that the water is hot and circulating? You should be able to feel warm/hot hoses at each of the radiators. If not, a possible circulating pump issue or a system air lock. Most of this is pretty easy to troubleshoot by a simple touch of the hand. I would not assume that the circuit board is bad as it is always easy to blame the black box. Probably something simple so keep you thoughts along those lines. If it is time for deeper troubleshooting then then the next step is to fully understand the system and start at the beginning. Good luck. Hope you get some heat going soon. Jim

 

[DrDave]

There does seem to be heat getting to each coil. All the batteries have been replaced in the thermostats. I have tried summer and winter valve positions. I am going to top up the level of the heat transfer fluid. Wondering if the previous owner used RV antifreeze, which might not carry as much heat. Will try to locate and jump one of the aqua stats.

 

[KMAL]

There does seem to be heat getting to each coil. All the batteries have been replaced in the thermostats. I have tried summer and winter valve positions. I am going to top up the level of the heat transfer fluid. Wondering if the previous owner used RV antifreeze, which might not carry as much heat. Will try to locate and jump one of the aqua stats.

Polypropylene glycol is commonly used in these systems. Have you checked or replaced your aquastats? Even if the thermostat is calling for heat - if the aqaustats do not register enough heat at the radiators, they will not allow for the fans to turn on. In my experience the aqaustats can be set for quite high temps and are a common point of failure on these systems. You can also remove the aquastats so that the fan simply comes on when the thermostat calls for heat regardless of whether the radiators have enough heat. The ITR phone techs, in my experience are good - call them if you have not.

 

[DDW]

On an ITR, all of the thermostats and the fan wiring are home runs to the control box, which switches everything and supplies the power. The thermostat closes, telling the control box there is call for heat. This will fire the burner (unless the water is already to temp) and start the circulation pump, and provide power to the fan associated with that thermostat. All of this is easily checked. Thermostat closed will short the thermostat input to the thermostat common terminal, for example T1 -> Tc. Check for voltage between them, should be 0V if calling for heat. Then the fan output should come live to 12V, example F1 will measure 12V to ground. If those are true then there is something local to the heat exchanger.

As commonly installed there are two things in series with fan power from the control box, a speed switch and an aquastat. The speed switch as supplied by ITR has Hi, Lo, and Off positions. Hi passes voltage through, Off is off, and Lo passes voltage through a wire wound resistor to drop the voltage to the fan. The aquastat is a snap stat that will be open until temperature is reached, then will close. Other than a fault in the wire itself or the fan, those are the places to look.

 

[Portage_Bay]

Because all of your zone fans are not coming on it is unlikely aquastats at the individual units. I would suspect the fluid temp could be low enough to not trigger the aquastats. Easily checked with an IR gun, see if the fluid is up to temp. That problem drove me nuts at one time. Feeling to see of the fluid is hot is not good enough .

 

[Mac2]

OP stated there “seems” to be heat at the coils. If the system is up to temp, you can barely hold on to the heated pipes. On both my heater installs, I had a hell of a time getting rid of the air locks. Was pex or rubber hose used? If there’s an air lock (typically happens when you fill the system) you can feel your way to the air lock-typically a high point/loop. They make bleeders you can add to the high points to release the air. I used clear/white pex, which made it easy to see the air lock. You can also beat the **** out of the line to help the air locks break up. By chance have you refilled the system recently? Side note: I have one aquastat for the whole system.

 

[DDW]

The aquastat is easy to check. Voltmeter across its terminals. Will be zero or close to zero if the fan is running, and 12V if the fan is energized by the control but not hot enough for the thermostat. Or just short across it temporarily to see if the fan comes on. In 5 minutes you'll know.